Yellow-brown (and therefore probably dry) or pale yellow, (and therefore possibly dog wee)? Phil J

Temagen, I note another question from a guest which appears to be connected with this question - always best to respond under your original question.
You say you have no dog, and the ground is damp - can I ask what preparation you did before the turf was laid? Did you dig over the whole area, removing debris as you went, then tread it all down with your heels all over, then rake up to a fine tilth, re level and then lay the turf? Because the other explanation for your yellow patches could be poor contact with the soil beneath, or sited on soil which contains debris.